SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '737233111c455fbb44fec3fee7b65089c3885300e3543ffbacdfa39f4ff7cf54' 
  AND token = 'OsqlIVrATEIV2XDb/fJg3V87VcpVfGYpsI4VF1O3zLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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