SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f93551b2c31848e918ca85ec9ac7add4c3347e8797985303334ba4593288bd9c' 
  AND token = 'LNejO1eg22du7ck9izOqYtKhbiOarcsGoCHGLlVfnq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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