SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa63d504b2082a51968f14b460253b6c71708c4d49eca2c994f9396afc5ad76a' 
  AND token = 'q2yzLmChNc3qRmVa5GqZY5ZFLpGekjVs4KhDbgiEO7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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