SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aab4ca5adde598a0011f365b34626967bcd2e4ede6d7d4f822021869afe8185e' 
  AND token = 'zn+TxKICjxDuPEep3vX9TQ5+jgWBORjDMGPBvMrz3ME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}