SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98712a60b45864953420d00f2798b1d460b6919303dd255d106f4be169b4f609' 
  AND token = 'bjvHGTzL1KuBv5Pv9weVVdtp1eXM7S/CRFQHYYiW42I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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