SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e568e38882be803b05238405066d9704a95e56daeb798aaba1dad0a3e607868a' 
  AND token = 've37FGfAA8uHDDZhx/cetjfSeRgviGpqbe/YoM9odug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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