SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a97c8e1ee7368427bb048c54d24b9e89e778cd48040e69ba320839e76fdeb72c' 
  AND token = 'Snlq5CPnhfrmf1ELBkWpvVUsmCnY3Fp2yBYupacgqXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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