SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8916b8b91aea7f7a0e68e77e343618884f5d3ec9ff8d72377d046e00cf484aad' 
  AND token = '5eGe27l+oFQKSOZioYmum7ebpN1QlKMxO8oaFwXHTsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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