SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8e914bcfcbe5e336837f2c98f0b262f95736937f5cc4fa114086aa4be7bc423' 
  AND token = 'T1zhh9n9Qxg3KsF+ZJAaXQGDUunrnSpk7mDrwn+nM94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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