SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48d315be6d6308d9de3fc1a9de551bb62f70ebc3234309111853504ee03c0210' 
  AND token = 'IJXQkM/eIRnq6foYK0eVOZ5+09EuxPAdzeO2ppUW9LM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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