SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfcf57a8582f21c94f21ca056fdf81141a2501ef465e73add64a1aa4825d0884' 
  AND token = 'iT4WBdcvhgFllINvt01lvkaQlpGtT/6tDxqJiS50aPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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