SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '493ffe0611d0ef14e3acf728270143886f382e0aebaf8226149246ef19cdc4f0' 
  AND token = '3mYX1oZKlrK6WsiAPVYE+YxFU1zT6d53zXRfMqctAF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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