SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a242bf76677b16c797c9eff8bc8aacfd4dfd9fb01b5fbe60a86361ef012ab510' 
  AND token = 'FFgtXn89xvDsKgrQa7JqVGmanVFACCHVYvTaqqAzYzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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