SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64ee0057cf7fa78a8e51727d450a0e1509425e61c922abe3f7175f176b2d1bc2' 
  AND token = 'VYjhy4uzm9B/bvAfB/hxNfmiCPtqTIGItI03BgBXy+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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