SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd65b748580214e89c2bc0fe89adc5163dd98335ea589ee4b2407a336927e7b0e' 
  AND token = 'LfIOytsB0YjFj90//r9e+o1basIszQ271oo2EyESh8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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