SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec2fdea0127375454891537b3543698fc3546d1829a3402b899530c6a9a6b200' 
  AND token = '2di4cxZdB49QCmd8+zlc9+iw6hOTYOQyPRFn0vMorHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}