SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc54a413287e744c880ad3097ee95e6585cc956003ff719861d206b792048df6' 
  AND token = 'CqBGkvFSw9I4b+/pKQ9Zcm3NGmpiE7Im4J/3BBK2tK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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