SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5048b59840aa36f7cc0a925ce4de117d7e36c0e4050d1eecd7c657e0d77b379' 
  AND token = 'ewmlXvuLFj+FUMTaM/H3Qoug/qYWnv3KQa/20w3RKIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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