SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a3ae551d5ec458e52f6922e218c70d4de8a01c9f113b520aac91ebab84cea8e' 
  AND token = 'aSPPkiUS33zEoL3sHWzylITa1Y33l8CLNcSTwhEmKjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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