SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92f8e230f1329d683ee010e35e6d36367803e56033cc1de4061d06bbc2230743' 
  AND token = '49iBmAeJWF2lvj7qhZNSMWBgP2ASFBznc97MKgKiVo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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