SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5e1b10e76597f423e166696bb9131bbc631a80e4b6b10113a4fb76cd034e776' 
  AND token = 'yKmDlB8DjO3NbRm8rf8lkns6MEJA8VSjCVdmmpRCKx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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