SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e6df94769fbe3cffe9d4d9512aa64274ba1339739e38064bc25fbbaca854886' 
  AND token = 'pe5QwwvNQqk/+R3wum5l/E6QwXPa33IOLtQKFnZqzHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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