SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7561b27fc4efdc9df6209bb87b9b0efa4e0da7dd9eb3172fd78790f597667244' 
  AND token = 're/h7/yUm9+65tNYtMDDN7pNW318XvQhA6i2NBENTZw=' 
  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"
    }
  }
}