SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56c3149a311fcacf37a442e2fdcfbbc1c701e933219b736d045a88cdfec418cb' 
  AND token = 'r6PlaYdEuus4sGLxtsx7v0VU+c2h/4tldu100qnbjuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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