SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34e262a41a1630a41519e0f6466da285a181bd947557699f681904becda5e022' 
  AND token = 'Io95KPj/9agzmB3iW5U3sZMHt1pSBP7cntfR4UORRDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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