SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb43cca75db32ac6a413e77c6d279b26c5fb2173549058a8a572b6f11104ae7d' 
  AND token = 'locoUcZLMNvZhW+ik09ydHD3pNSab3xFmuh/y6HAhbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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