SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03cdedc808c058dd3b77945577bba93957bdc65df24351cae1d04709cd4197ab' 
  AND token = 'isf9x/xKPFv94CHI4nENB2CCJGhenAHWapq0QTBQKfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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