SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1191a15fd441b2229992bab9f66df9f8ef9103db7bda40e867a9ae3cb15ba407' 
  AND token = 'y647/lTpyIwqm9AGuOklcAAHPh7xKjkd0lEcQDgd3Wc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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