SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1afd0de7d002cd356e3ee3607d6c6b74c962380646ade23d2d16d716f78483ed' 
  AND token = 'S87dP3coDkC2NkaQj80iPRJdKs1DSQGgzFDNulwSOxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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