SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba54f2514f2003ec078914aa15a454b2a2cd117af0098872460a517e68577248' 
  AND token = 'AuvF1gO84+aCHNyd27Fvxk0waqfM4Xq5ZXwA0SNGq34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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