SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87a42151dc5b1f5db643ea69561a728b480bc81845aec90691f7791f9a2a12ac' 
  AND token = 'FDwX59cyBh6f0LdLDiH4lifb0DvV2QvCiwIhFm+MFgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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