SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c7c4ecd08d3978ccde019133a53cfe196456bd3f0d94850e36a8850ec67b6b0' 
  AND token = 'SjyVqFPUipKihjB3BwubhuzxR1PjcfLjIPXr/FtaDiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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