SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76b9eb80724b78002595bdd682501c625f02815fdb16b508e0442395f427c31c' 
  AND token = 'Dw824gaBkD1QCxX6ghQTyXzg1ljfphelqGvPbLj7n+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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