SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b08b13cad07f20392256e8311cf26fb93223573df9b75c7e70e85a63f9f07deb' 
  AND token = '6yQxqoCkhPQBgrlSuXBmM5feqQ4X3gq+k2E479u0rjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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