SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfa06bf694153c5b712313afe4ac7f97b7cde78936d8e158d660737f792ae408' 
  AND token = 't+9mJxtzw6gNOgfhvmDSVsGXZ7UxQh3IPHNLR+cCEPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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