SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc0e54237f007aa8765ca8f6f5eda31bc27b9f96629a3177d57a40d151072815' 
  AND token = 'WrzJmeiMRxPss46ow6+vxwOpjftgQuCNu2dh+nSmiZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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