SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0ff06838a1868b3491d25341aa2e995e053cf004c3eafa347a97883306f21d9' 
  AND token = 'obzwBP3ehH7JEKXb47QAnFTc7xt1nlI/mkfIOgCmk1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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