SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88b0bde3f5367be3c1ed11e658a28e98b9f28e0a680ec0094c94569df6ef2930' 
  AND token = 'eB4OOCmdAdIqe0rgkSf7M+/8PMSxQR72hIjhNBHprds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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