SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b0d289fbff45a0143e1de78ae6d769f20b819f73f24604c71ecf33c39904b4b' 
  AND token = 'Vy1AyhQN3CqItHVRfIswyDCFLsUuGTl2KEtRksVx9Aw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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