SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c81a54e0f69780e1a23810612996913e5691680513ace4dc6d5797a0164699a' 
  AND token = '9Y+A+u+yEAOQFpsWNDJDmU0QkpQ+T60F2tnvTsR0Puo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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