SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbf384b047300b60905b27001992584fc19121e3f1af15b09020725c7255c5c6' 
  AND token = 'ZfxCkuvWyaU1hWP+cCS22iCDZQIoZDtSudmtZFFRJi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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