SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '559eb787239b1ca4ce9673c20cebd95201d375e3523e80b214da07d19514b60f' 
  AND token = 'RZ/bExPli/BHg6MP8h8UaUhNyfsfUY0slY9JhVVxxl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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