SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9309e80b3c446a79f870c2d7cb80f4b9a464cccee02c61ac07786a2f428c245' 
  AND token = '38z8DIzQZXESakbAjMMlRi/L36Lt6/DqcvAuYKGNHVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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