SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4c9d0ee86f9ac3238c3f722bcddf01f23391114c683eb2fe368cc21b1f3ab1d' 
  AND token = 'gxvbxECZASVm+tEXoMuMzE3HscMyC3wJcw1F+X5bAa4=' 
  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"
    }
  }
}