SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8126a5bd9749f7dc25d2f7813001bc537774dfea9568c937aced3462f9f650c7' 
  AND token = '4JboP3/J1pU5qsW7OCwhsO/Jx2+Z+T//UiVn+fYGDOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}