SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd597b57f37eac76bac1a1cb95cd483053b18617b82485e7f09c5382ca8b667da' 
  AND token = 'nj2VdzR3nIMueiSUasia5aMbMpLcZmr1rrjp5YOIJrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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