SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f53012c52811cc1c44931cb890b429a231d7e7d8da03f08a1f945b77556d697c' 
  AND token = '7Dfj4PBIXvxhG2BgtW/JClU/FAhZdw8kxDg9FO1JGCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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