SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce7acf2c3b599d2f799b207302df5938dabb775d1fa6ccb45d36b474e0aaf69b' 
  AND token = 'sxOsulBVIsscdSI9nkDjQwaSikr4Ehg5BGTRtblvlI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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