SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11a29cee69cbca19fcbcdf1d35f6116af21fe76b924033c5851d4ead07527b0c' 
  AND token = 'szo/czDk4fKkGv6YEqFMHeCjwMOpOr3JaY9wxxLAa08=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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