SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b909ed2a471a3beb34bd265d3c71097b9eaba8a2b5373cf302ae13feba56daec' 
  AND token = 'pVOsKfsoo7SqkoZkCt4rTVk5shgL5RmEAKrKlBj77gU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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