SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c84debbea8da22f1a9743012e02b4a7eb19ebd874b4e50452622aaf66f9fd60' 
  AND token = 'yd2Rw7DkmvbulyJPMDEAtcRidsER1BAsx+U5PCxzJeI=' 
  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"
    }
  }
}