SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72a22ce835d3fa6e860c0d11f1deca984ec5639e65ce27ee5ecc9dfab0b7ff67' 
  AND token = 'LkxAU4vj7DoZWEiqFpUCuUue7Gejx4BQv63n9peOcno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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