SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37e695250ccf06378809cf1dbe5735e8fcacdec2e94e6d40dcc8914963227f90' 
  AND token = '6pZV3JosHUqLa8QJGgzK4PulvAwScLkU20fi4WZorhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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