SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c034e85e73250046b12535ee936c0641e10295d215f982df40b61e2cefb1a4fb' 
  AND token = 'g1bMiVi+7VCETPvlKNM+1ANvl6LoN9jn+WtoVPIF2es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}